Furnace arch construction



July 2, 1940.

H. R. SIEB ERT FURNACE ARCH CONSTRUCTION Filed Aug. 17, 1939 2Sheets-Sheet 1 cc, a ",5

INVENTOR 17 (171. Saew f KE MV IHIIIl ATTC R N EY July 2, 1940. H, EBRT- 2,206,679

FURNACE ARCH CONSTRUCT ION Filed Aug. 17, 1939 2 Sheets-Sheet 2 INVENTORfi mioiii Patented my 2. 1940 I "PATENT w es:

I'UINAOI ARCH CONSTRUCTION nm asubm. smmcunuuam to American smelting andleiining'Oompany, New York, N. I, a corporation of New Jersey IApplication August 11. use. serum No. zoom 1. sum. (or. sec-m Thisinvention relates tofurnace roofs aim more particularly to an arch roofconstruction for circular metallurgical furnaces, such, for example, asGodfrey masters or the like.

I 'An object of the invention is to provide a sprung arch roofconstruction having novel and improved means to prevent the contractionor expansion of the materials from causing deformation of the roof.

I Another'obiect is to provide a construction wherein the'material ofthe arch is maintained imder substantially constant compression,regardless of changes in dimension thereof due to expansionandcontraction.

Another object is to provide a novel and. improved means for closing thecenter of the arch about the eccentric feed hopper.

Another object is to provide a convenient. dependable and eiiicientconstruction of the type above indicated.

Various other obiects and advantages will be apparent as the nature ofthe inventionis more fully disclosed.

Although the novel features which are believed I to be characteristic ofthis invention are pointed out more particularly in the claims appendedhereto, the nature of the invention will be better understood byreferring to the following description, taken in connection with theaccom- Ii panylns drawings, in which a specific embodiment thereof hasbeen shown-for the purposes of illustration. I

In the-drawings: Fig. 1 is a top plan view of a furnace'roof I embodyingthe present invention;

Fig. 2 is a transverse section, taken on the line- 2-2 of Fig. 1:

Fig. 3 is an'enlarged detail view showing the center closure andsupporting means; 9 Fig. 4 is a transverse section taken on the line 4-4of Fig. 3;

Fig. 5 is a plan view of the spring coupling means for theouter roofband; and

Fig.6 is a side elevation of the coupling means I Of Fig. 5.

The invention is shown by way of illustration as embodied in a Godfreymaster of generally standard construction comprising circular side wallsIt and a rotating turntable or hearth H D supported on a frame If androtatably mounted by means of a bearing ll. Wheels ll riding on acircular rail l5 serve to balance and help to support the assembly. 'Theturntable ll may be rotated by 'suitable means,.such' as a gear train Ill, driven by suitable means, such as a belt pulley n. The char e isapplied togthe hearth near the center thereof by an eccentric feed spout20. The roaster is provided with'suitable rabble arms (not shown)ofstandard construction for advancing the charge radially to aperipheral I discharge spout II. 'It' is to be und'erstood thattheportions of the roaster thus far described are of standardconstruction and that only so much thereof has been set forth as isnecessary to an understanding of the present invention. Furw thermore,the invention is also applicable to other types of furnaces. Theturntable or hearth may. for example, be made stationary and the furnacemay be provided with rotating rabble arms, as is well known in the art.The invention may aisobe applied to other circular furnaces of thegeneral type herein disclosed.

In accordance with the present invention. the roaster is provided withan arched roof II formed of suitable refractory-brick and sprung betweenthe top portions of the side walls iii. The roof is so constructedthatit is normally held in position by the keystone sheet of the arch.The feed spout 20, in the embodiment shown. is clamped in a split ringas which, in turn, is cccentrlcally mounted in a second split ring I! towhich it may be secured by tie rods 20, the parts being welded orotherwise secured as may be desired. 'ihe arch roof I! is provided witha central opening 2 formed by ametal ring II which .is secured to theinnermost-row of bricks St. The

ring is concentrically mounted within the ring 8! and is held by a setof radial compres sion springs 82. 'I'hering is shown as formed insections so that it may expand or contract as may be required toaccommodate itself to changes in the dimension of the arch caused byexpansion or contraction of the brickwork- Thesprings I2 are adapted tosupp y the necessary pressure for maintaining the arch in position at soall times, regardless of any changes in dimensions thereof. a

For closing the opening 28, a refractory plate ll is provided. Thisplate may be formed of refractory cement cast about the feed spout 2|and supported by a bottom flange it formed on said spout. Suitablereinforcing rods 31 may be embedded in the refractory plate for strengthening the assembly. These rods are preferably covered by a soft material88, such as. several layers of roofing paper or the like, so as topreventthe expansion and contraction of the rods from cracking therefractory material. Theplate it, closes the opening II and slidablyengageetheinnermoet-row of brick 8|. I 7 ll bars 42 and adjusting nuts46. The springs 45 are designed and constructed to hold the band M undersufficient tension tocause the roof and walls to withstand the action ofthe springs 32 and, at the same time, to permit alimited amount ofradial movement as may be required due to the expansion and contractionof the brickwork.

The walls it are shown as provided with ex pansion joints 41 whichextend to a point at least.

below the turntable it so as to permit the walls to expand and contractwith the roof. In order to prevent theband M" from sliding upwardly, aplurality of tie-rods 5t may be provided which extend over the band itdownwardly on the outside of the walls, I0 and are anchored by bolts 58set in pockets of concrete 52 formed in said walls. I

, It is to be understood that the roof may be provided with a suitableofitake flue 5t and with suitable burner openings M in accordance withMown practice.

In the operation of this invention, the charge is fed through the feedspout 2t and is advanced outwardly on the turntable by the rabble arms(not shown) until it is peripherally discharged through the dischargespout ii. The: charge is heated in the usual manner by the burnersextending through the burner openings 26, the combustion and roastinggases being removed through the ofl'take flue '69. This type of furnaceis subjected to extreme temperature varia-- tions which cause .thebrickwork to expand and contract by an amount which, at times, may besuliicient to cause the arch to collapse unless temporary supports areused during the shut down periods. The present invention eliminates thisdimculty, however, by maintaining the arch under suflicient radialcompression atall times, 4 due to the action of the springs 32 and 45,to

prevent the same from buckling or collapsing. The life of the brickworkis thus materially in-v creased, and the necessity for shutting down theroaster at frequent intervals for repairing or 1 rebuilding the arch isavoided. 1

Although a specific embodiment of the invention has been shown hereinfor purposes of illustration, it is to be understood that the inventionis capable of many uses, as will be readily apparent to a person skilledin the art, and that, accordingly, various changes and modifications maybe made within the scope of the appended claims.

What is claimed is:

1. An arch roof for a circular furnace or the like comprising a sprungarch having a central opening, and spring means positioned. in saidcentral opening for maintaining said arch under compression sufiicient.to support the same as the dimensions of the arch change due toexpansion and contraction of the materials thereof.

2. An arch roof for a circular furnace or the like comprising a sprungarch having a central opening, an expansible ring in said opening andresilient means applying radial pressure to said ring sufllcient tosupport said arch du ng aaoaevo changes in dimensions thereof caused byexpansion and contraction of the material.

3. An arch roof fora circular furnace or the like comprising a sprungarch having a central opening, an expansible ring in said opening, a

I rigid member positioned concentrically within said ring, ,and springmeans extending between said ring and said memberapplyingradial pressureto said ring suflicient to support said arch during changes indimensions thereof caused by expansion and contraction of the material.

4. A furnace comprising circular side walls, a circular archroof sprungfrom said side walls,

,' said roof having a central opening, resilient means in said opening,applying radial pressure sufiicient to support said arch during changesin dimensions thereof caused by contraction of the material when thefurnace is shut down, a retaining band around said side walls insubstantial alignment with said roof, and resilient means holding saidretaining band under tension adapted to counteract the thrust of saidroof ,produced by said first resilient means.

5. A furnace comprising circular side walls, a

- circular arch sprung from said side walls, said arch having a centralopening, resilient-means in said opening applying radial pressuresumcient to support said arch during changes in dimensions thereof dueto contraction when the furnace is shut down, a retaining band aroundsaid side walls in substantial alignment with said roof, and resilientmeans holding said retaining band under tension adapted to counteractthe thrust of said roof produced by said first resilient means, saidside walls having expansion joints to permit movement thereof with saidroof as the materials expand and contract.

6. A furnace comprising circular side walls, a circular arch roof sprungfrom said side walls, said roof having a central opening, resilientmeans in said opening applying radial pressure suflicient to supportsaid arch during changes in dimensions thereof, a retaining band aroundsaid side walls in substantial alignment with said roof, resilient meansholding said retaining band under tension adapted to counteractthethrust of said roof produced by said first resilient means, andtie-rods engaging said band, said tie-rods extending downwardly oversaid wall and being anchored thereto to prevent displacement of saidband.

'7. A furnace comprising a sprung arch of refractory brick having acentral opening, an expansible ring in said opening engaging the innerrow of brick, a second ring within said opening concentric with saidfirst ring, spring means extending between said first and second ringsto first ring, spring means extending between said first and secondrings to apply radial pressureto said first ring, a feed spout mountedeccentrically within said second ring, and a refractory plate carried bysaid feed. spout and closing said central opening, said refractory platecomprising a cast refractory having a plurality of metal materialadapted to prevent cracking of therej reinforcing members disposedtherein, said reinforcing members having a covering 01 soft fractory dueto expansion or contraction of'said members. I

9. A metallurgical furnace of the Godfrey type having an arch sprungfrom the upper "portion of the furnace sidewall, an expansible ring inthe center of said arch, a ring of lesser diameter within saidexpansible ring, coil springs between said rings, a charge hoppercarried by'said ring at lesser diameter, a retaining band encircling the1- perimeter of said arch, and resilient means maintaining saidretaining band under tension.

10. In a circular furnace arch roof having a v central opening,resilient means mounted within said opening exerting pressure radiallytoward the periphery of said arch, peripheral resilient means opposingthe radially exerted pressure aforesaid, and charging means extendingthrough said central opening and positioned eccentrically with respectthereto. i v

H. R. smnm'r.

